Falling levels of nitrogen in the atmosphere across Europe may be much more economically beneficial than previously believed, according to a recent study.

Indeed, scientists think the UK alone benefits by around £65 million a year. Levels of atmospheric nitrogen have fallen by around a quarter in Europe since 1990, mostly because of tighter rules on emissions from engines and industry. Scientists are still working to understand the consequences.

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This is difficult, because excess nitrogen affects the benefits that nature gives us (known as 'ecosystem services') in many different ways — some positive and some harmful. For example, nitrogen is an important plant nutrient, which means services that depend on plant growth, such as crops and timber from woodlands, will benefit from more of it in the atmosphere. Conversely, falling nitrogen levels will harm these services - so cutting pollution costs the economy money.

Too much nitrogen harms other ecosystem services, though. For example, it reduces plant biodiversity and tends to favour the growth of rough, weedy vegetation like nettles and coarse grasses, which many people think makes the landscape look scruffy. Too much nitrogen therefore reduces our enjoyment of nature.

The study, published in the journal Ecosystem Services, is the first to take a comprehensive look at the impact of falling nitrogen levels on a range of ecosystem services and hence on the economy. Previous studies have tended to focus on 'provisioning' services like timber production and 'regulating' services like carbon sequestration, which are relatively easy to value. They have done this at the expense of 'cultural' services like tourism and appreciation of the natural environment. These do have value, but are harder to measure and quantify.